It can be a laxative. But catahrsis has other meanings and uses as well. To rid yourself of grief is cathartic. Mainly, it just means to get something out of your sytem that is making you feel unwell .
All medications should be OKed by your doctor while you are pregnant. What is safe in mid pregnancy isn't OK near delivery, what is not safe early on, may be safe later on. Only you and your doctor...